The claim that vitamin C is useful in the treatment of cancer is largely attributable to Linus Pauling, Ph.D. As, vitamins C have an anti-oxidant effect and are considered important neutralizers of free radicals. A few studies of the role of vitamin C in protecting against breast cancer have produced contradictory results. Fruits (black currants, grapefruit and grapefruit juice, mangoes, oranges and orange juice, strawberries, and watermelon) and vegetables (asparagus, broccoli, brussels sprouts, cauliflower, lettuce, mustard greens, parsley, green peppers, spinach, and tomato) are best sources of vitamin C.
Linus Pauling was diagnosed with cancer of the prostate. He did not interpret this diagnosis as contradicting his theories, however:
I've never contended that Vitamin C in large doses will protect you absolutely against any disease ... many men die of prostate cancer at age 60 or 70. Taking Vitamin C may mean that my curve shifted 20 years. (John Woestendiek, 2002)
Pauling remained convinced that vitamin C was almost totally effective against the common cold. Pauling routinely took about 10 grams of vitamin C a day. When he was traveling and felt tired or thought he felt a cold coming on, he sometimes increased his dosage to as much as 50 grams. The fact that the 10 grams had not been sufficient in the first place did not shake his confidence in the vitamin. And when he had symptoms that other people might think of as a cold, such as a bad runny nose or a cough, he attributed them to allergies.
For a number of years, the crusade for vitamin C didn't seem to be getting very far. Pauling "felt rather discouraged, because it seemed that, although our work had progressed well, it was still not accepted by most physicians and in particular by medical authorities." (Linus Pauling Institute 1993).In the early 1990s, however, the tide of opinion seemed to be changing.................
